This section evaluates the SOP of the system. The instantaneous secrecy rate \(C_S\)  is defined as the difference between the legitimate channel capacity and the wiretap channel capacity and is expressed as [1]}
\(C_S=\max \left\lbrace \log _2\left(\frac{{1+{\Gamma }_{D}}}{1+{\Gamma }_{E}}\right),0\right\rbrace .\) 
